Monorail switching device

ABSTRACT

A vehicle switching arrangement comprises an overhead monorail guideway that includes a mainline section and a diverging section merging with the mainline section to define a switching station. In addition, a bogie unit is arranged for rollable transport along the guideway and includes port and starboard main wheels rollably engaging the guideway. The bogie unit also includes a guide arrangement for selectively acting against the guideway to load either the port or the starboard main wheels in excess of the normal vehicle load thereof for establishing a vehicle heading through the switching station. Furthermore, stationary fail-safe cams are provided on the guideway to cooperate with cam followers carried by the bogie unit for ensuring safe transit through the switching station in the event of malfunction.

United States Patent Corey [54] MONORAIL SWITCHING DEVICE [72] Inventor: Robert W. Corey, 2405 Skyview,

Richardson, Tex. 75080 [22] Filed: Oct. 27, I970 [21] Appl. No.: 84,274

[52] [1.5. Cl ..l04/l05, 105/155 [51] Int. Cl. ..E0lb 25/26 [58] Held of Search ..l04/38, 89, 94, 95, 96, 104,

[56] References Cited UNITED STATES PATENTS 997,690 7/1911 Moore 105/154 3,059,591 10/1962 Chadenson 104/94 2,602,710 7/1952 Gesner ..104/94 3 ,098,454 7/ 1963 Maestrelli ..104/130 640,050 12/1899 Von Thal 105/ 154 3,152,559 10/1964 l-larshberger ..104/130 3,225,704 12/ 1 965 Gilvar 104/ l 30 3,086,478 4/1963 Schreyer ..104l94 Nov. 14, 1972 Primary Examiner-Gerald M. Forlenza Assistant ExaminerD. W. Keen Attorney-Olson, Trexler, Wolters & Bushnell [57] ABSTRACT A vehicle switching arrangement comprises an overhead monorail guideway that includes a mainline section and a diverging section merging with the mainline section to define a switching station. In addition, a bogie unit is arranged for rollable transport along the guideway and includes port and starboard main wheels rollably engaging the guideway. The bogie unit also includes a guide arrangement for selectively acting against the guideway to load either the port or the starboard main wheels in excess of the normal vehicle load thereof for establishing a vehicle heading through the switching station. Furthermore, stationary fail-safe cams are provided on the guideway to cooperate with cam followers carried by the bogie unit for ensuring safe transit through the switching station in the event of malfunction.

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.l |l||||||.llllllll.l'l'lll'l'llltulllllllll- P'ATENTED NOV 14 e912 SHEEI 9 OF 9 MONORAIL SWITCHING DEVICE BACKGROUND OF THE. INVENTION This invention relates generally to monorail transportation systems and more particularly to devices for switching a monorail vehicle from one heading to another.

According to conventional practice, mechanical switching arrangements for altering the direction of a transportation vehicle include a section of movable track which is pivoted or otherwise shifted in the route selection process. A considerable amount of power is commonly required to cause the movable track to execute these transitions and the process is time consuming. Slow switching of movable track sections can be permitted in transportation systems operating on a fixed schedule where the presence of a vehicle at a particular switch and at a particular time can be predicted; and having advance knowledge of vehicle destination, track personnel can have the switch readied for passage of the vehicle. Such complicated preparations are impossibly difl'icult in transportation systems operating in response to the demands on the system and without fixed schedules. The utilization of prior art switching arrangements of the movable track type has heretofore prevented demand systems from achieving their potential in speed and efficiency.

An important object of the present invention is therefore to provide a vehicle switching arrangement in which all the movable parts involved in route selection are carried onboard the vehicles.

A more general object of the invention is to provide a new and improved switching arrangement for trackborne vehicles.

Another object of the invention is to provide a vehicle switching arrangement which is fail-safe in operation.

Still another object of the invention is to provide a vehicle switching arrangement which achieves a coordinated response of switching elements carried respectively by a pair of coupled bogies.

A further object of the invention is to provide a vehicle switching arrangement which accomplishes a smooth transition of the vehicle through the switching station.

A yet further object of the invention is to provide a vehicle switching arrangement which is reliable in operation.

These and other objects and features of the invention will become more apparent from a consideration of the following descriptions.

BRIEF DESCRIPTION OF THE DRAWINGS In order that the principles of the present invention may be readily understood, a single embodiment thereof is shown in the accompanying drawings wherein:

FIG. I is a low-angle perspective view of an overhead monorail guideway arrangement constructed in accordance with the present invention and including a mainline section and a number of switching stations;

FIG. 2 is an enlarged and elevational view of the monorail guideway arrangement of FIG. 1 showing the guideway arrangement suspended from a support column and illustrating the normal running condition of the vehicle bogies in the guideway;

FIG. 3 is a bottom view of a guideway section defining the entrance portion of a switching station;

FIG. 4 is an enlarged cross-sectional view taken along the line 4-4 of FIG. 3;

FIG. 5 is an enlarged cross-sectional view taken along the line 5-5 of FIG. 3;

FIG. 6 is an enlarged cross-sectional view taken along the line 6-6 of FIG. 3;

FIG. 7 is an enlarged cross-sectional view taken along the line 77 of FIGS. 3 and 13;

FIG. 8 is a side elevational view of the guideway section of FIG. 3;

FIG. 9 is an enlarged and elevational view showing the action of the upper and lower guide wheels and cooperating guideway structure in negotiation of a switching station;

FIG. 10 is an enlarged perspective view of the bogies employed in driving the monorail vehicle of the present invention, the means for uniting the bogies and the lower guide wheel assemblies being removed for clarity in illustrating various other arrangements;

FIG. 11 is a view similar to the showing of FIG. 10, illustrating the means for uniting the bogies but with certain of the related structures removed and others shown in broken lines for clarity of illustration;

FIG. 12 is an enlarged cross-sectional view of the main drive wheels used in the bogies;

FIG. 13 is a bottom view of a left-tum switching station constructed in accordance with the present invention;

FIG. 14 is a bottom view of a merging switching station construction in compliance with the present invention;

FIG. 15 is a low angle perspective view showing the fail-safe mechanism employed in the present invention;

FIG. 16 is a longitudinal cross-sectional view taken through the guideway of the invention and illustrating the power bus arrangement and cooperating takeoff used at a switching station;

FIG. 17 is an end elevational view of the guideway and bogie arrangements taken in partial cross-section to show the power bus arrangements and collectors and taken along the line 17-17 of FIG. 16, certain of the means for positioning the lateral power collectors being removed for clarity of illustration;

FIG. 18 is a longitudinal section view of the fluid-actuated jack used in manipulating the upper and lower guide wheels of the bogie units;

FIG. 19 is an enlarged cross-sectional view taken substantially along the line 19-19 of FIG. 18;

FIG. 20 is an enlarged perspective view of a lower guide wheel assembly and related electrical switching components;

FIG. 21 is an enlarged, fragmentary plan view of the lateral power collectors and related positioning means used in picking off electrical power from the guideway during transit of a bogie unit through a switching station, taken along the line 2I-21 of FIG. 16;

FIG. 22 is a fragmentary, side elevational view of the cam and link members used with the positioning arrangement of FIG. 21',

FIG. 23 is an enlarged, side elevational view of the electrical switching arrangements used with the lower guide wheel assembly of FIG. 20;

FIG. 24 is a fragmentary plan view of the electrical switching arrangements of FIG. 23; and

sensed by the associated electrical switching arrangement.

DETAILED DESCRIPTION Referring now in detail to the drawings, specifically to FIG. 1, a portion of an overhead monorail transportation system constructed in compliance with the present invention is indicated generally by the reference numeral 30. The transportation system 30 includes: a guideway or trackage 32 which defines the transportation routes; a suitable number of horizontally spaced support columns or towers 34 which are mounted on concrete pedestals or footings 36 and from which the guideway is suspended, and a suitable number of transportation vehicles 38 which are adapted to run on the guideway 32. In order to afford flexibility in the routing of the vehicles 38, the guideway 32 is arranged to include a mainline section 40, a secondary line section 42 and a parking section 44, the secondary line section 42 and the parking section 44 diverging from the mainline section at switching stations 46. As will be appreciated, the transportation system of the invention includes a multiplicity of secondary line sections and parking sections in accordance with the requirements of the facility being served by the system. It is to be appreciated that the instant transportation system will include various boarding and destination stations and that the term diverging when applied to sections of the guideway 32 shall encompass switching stations which accomplish merging as well as shunting.

Referring to FIG. 2, the transportation vehicle 38 includes a suitably sprung suspension 48 which is hung from a pair of bogies 50 (one of which is shown) by means of a spindle 52. Each bogie 50 includes a pair of laterally aligned main drive wheels 54 which are rotatably mounted on a central main frame 56, and the guideway 32 comprises a hollow box girder unit 58 which surrounds the bogies 50 and defines bearing surfaces for the drive wheels 54. Each of the bogies 50 also includes a pair of upper guide wheels 60 which are eccentrically rotatably mounted on a shaft 62 as will be described more fully hereinafter. As will also be described more fully hereinafter, the guideway 32 additionally includes an overhead power bus arrangement 64 from which the bogies derive electrical energy for powering the vehicle 38.

The guideway 32 is suspended from the support columns 34 by means including a hanger bracket 66; and when it is desired to suspend the guideway resiliently, as for example on sections of the guideway where the vehicles 38 might reach top speed, the hanger bracket 66 is connected to a cable 68 which is threaded over pivoted sector plates 70 within the interior of the columns 34 to be fastened elsewhere in the column by means of a mounting bracket (not shown). A threaded stud 72 is swaged or otherwise suitably secured to the outer end of the cable 68 so that the hanger bracket 66 may be fastened to the end of the cable by means of an abutment plate 74 and locknuts 76. In addition, lateral stabilizer arms 78 are mounted in horizontal position between the side of the support column and the guideway.

In accordance with an important feature of the invention, the switching stations or sections of the guideway 32 are completely static; and all movable switching parts are carried by the vehicle 38. More specifically, to accomplish route selection at one of the switching sections, a selected set of the upper guide wheels 60, that is, either the port or starboard set of upper guide wheels, is urged into forcible engagement with the corresponding ceiling portion of the guideway so that substantially the entire vehicle load is borne by the corresponding main drive wheels 54. Where a turn in the route coincides with a switching maneuver, the main drive wheels on the inside of the turn are preferably selected to bear the vehicle load. This action of the upper drive wheels is continued during vehicle transit through the switch in order to establish the selected heading.

Continuing with reference to FIG. 2 and recalling that the guideway shown therein is an ordinary or normal running section of the guideway rather than a switching section thereof, the box girder comprising the guideway 32 is shown to include a first upper track plate 80, a first lower track plate 82 aligned beneath the upper track plate 80, a second upper track plate 84 spaced laterally from the first upper track plate 80, and a second lower track plate 86 aligned beneath the upper track plate 84. Turning for the moment to FIG. 13, the lower track plate 82 is seen to comprise a continuous mainline section 88 while the lower track plate 86 comprises a first section 90 which parallels the mainline section 88 and a second section 92 which diverges from the mainline section 88 to define a switch at the switching section 46. The guideway 32 additionally includes a lower track plate section 94 which parallels the diverging section 92 and which merges with the downstream portion of the diverging section 90 at a common section 96. It will be appreciated that the upper track plates corresponding to the lower track plates illustrated in FIG. 13 trace patterns similar to those shown and described relative to the lower track plates. It will also be appreciated that the space or slot defined between the track plate section 88 and 90 and between the track plate section 92 and 94 accommodate passage of the spindles 52 which support the vehicle 38 from the bogies 50.

It has been described hereinabove that the upper guide wheels are selectively actuated to impose substantially the entire vehicle load on one set of the main drive wheels during transit through a switch. This condition of a bogie 50 is illustrated in FIG. 9; and considering the direction of vehicle movement to be out of the page, the track plates and 82 become, respectively, the starboard upper and lower track plates. Correspondingly, the track plates 84 and 86 can be designated, respectively, the upper and lower port side track plates. Continuing in this framework of terminology, starboard upper guide wheel 60 is disposed in forcible engagement with the starboard upper track plate 80; and the starboard main drive wheel 54 forcibly engages the starboard lower track plate 82 through the reaction caused by its common connection to the central frame 56 of the bogie 50. Cooperatively, the port side upper guide wheel 60 is disposed out of engagement with the ceiling plate portions of the guideway.

Turning now to a consideration of P10. 10, the transportation vehicle 38 is seen to be suspended from a pair of bogies which, for purposes of distinction, shall be referred to as fore bogie 50a and aft bogie 50b. The bogies 50a and 50b are substantially identical except reversed in position, the bogie 50a being driven by a forwardly disposed electric drive motor 100 and the aft bogie being driven by a similar but rearwardly disposed electric drive motor 102. It should be observed that the fore and aft bogies are mechanically coupled exclusively through their common attachment to the vehicle 38. The motors 100 and 102 power the respective main drive wheels 54 by means of pulleys 104 mounted on the motor output shafts, endless flexible drive belts 106 and suitable pulleys secured to the drive wheels, as will be described more fully hereinafter with respect to H0. 12.

The main frame 56 forms the principal positional reference and mounting base for each bogie 50. For example, motor mounting arms 108 extend longitudinally from the main frame 56 to receive and be coupled with the housings of motors 100 and 102 respectively. In addition, laterally spaced upper guide wheel shaft mounting ears 110 are connected with the main frame 56 by shoulder brackets 112, the upper guide wheel shafts being joumalled in the ears 110. Considering FlG. 9 in conjunction with FIG. 10, the upper guide wheels 60 are rotatably mounted on shafts 1 14 which are, in turn, fastened to oppositely extending eccentric plates 116, the plates 116 being rigidly mounted on the guide wheel shaft 62.

In accordance with the features of the present invention, means are provided on the bogies 50 for restraining the transportation vehicle 38 against such forces and moments as wind and the centrifugal force encoun tered during negotiation of a curve. Specifically and with reference to FIG. 10, a pair of upper lateral restraint rollers 1 18 are mounted intermediate the fore and aft pairs of upper guide rollers 60 by means of mounting yokes which merge into the mounting shoulders 112. Each roller 118 is freely rotatably mounted on an upright shaft 122 affixed to the corresponding yoke 120. The upper lateral restraint rollers 118 are arranged to come into contact with the side of the guideway only when the bogie assembly leans away from the vertical direction. In addition, two sets of eccentrically mounted lower restraint wheels 124 are connected to the main frame 56 by means of longitudinally extending mounting arm assemblies 126. The lower lateral restraint wheels 124 are rotatably mounted on eccentrically disposed stub shafts 128, as is best shown in FIG. 9; and these lower lateral restraint wheels may be preloaded against the lower sides of the guideway 32 by springs or other suitable means, not shown. ln order to provide contact surfaces for the lower lateral restraint wheels 124, the lower track plates 82 and 86 are provided with upturned flanges 130 disposed to confront the edges of the lower lateral restraint wheels. Continuing with reference to FIG. 9, it is advantageous to provide the main drive wheels 54 with tubeless pneumatic tires 132; and in order to protect against mishaps which might occur in the event of a flat tire or the unintentional overloading of the vehicle, metal safety wheels 134 are mounted on the hubs of wheels 54 to rotate therewith. The safety wheels 134 are of somewhat lesser diameter than the diameter of main drive wheels 54 when the latter are under normal load. Thus, the safety wheels do not ordinarily engage the track plates of guideway 32.

In compliance with the features of the present inven tion, the activities of the upper guide wheels 60 are coordinated in order to insure that all of the guide wheels of the fore and aft bogies 50a and 50b move in unison. Referring to FIG. 11, the means for coordinating the action of the upper guide wheels 60 include a single pneumatic actuating cylinder or jack 136 and a cable-and-pulley unit 138. The cylinder 136 is affixed to the central frame 56 of aft bogie 50b by a bracket 140, and the cylinder 136 includes an extensible and retractable piston rod 142 which is pivotally mounted to a radial arm 144. The arm 144 is rigidly mounted on a pulley 146 which is, in turn, non-rotatably mounted on the forward upper guide wheel shaft of the bogie 50b. The cylinder 136 is thus capable of directing the forward pair of upper guide wheels into and out of forcible engagement with the ceiling of the guideway. In order to coordinate the movements of the rear pair of upper guide wheels with the forward pair, the cableand-pulley unit 138 includes a pulley 147 which is nonrotatably affixed to the rear upper guide wheel shaft 62, and an endless cable 148 is threaded over the pulleys 147 and 148 in the manner illustrated. In similar manner, the forward and rear upper guide wheel shafts 62 of fore bogie 50a are coupled for coordinated action by components of the cable-and-pulley unit 138. Specifically, a pulley 150 is non-rotatably secured to the forward upper guide wheel shaft, a pulley 152 is non-rotatably mounted to the rear upper guide wheel shaft, and an endless cable 154 is threaded over the pulleys 150 and 152 in the manner illustrated in PK]. 1 1.

In order to coordinate the upper guide wheels of bogies 50a and 50b, the cable-and-pulley unit 138 includes an endless cable 156 which is threaded, as shown, over the upper sheave portion of a double pulley 158 which is associated with bogie 50a and the upper sheave portion of a double pulley 160 which is associated with the aft bogie 50b. The cable 156 is situated generally interjacent the pairs of drive wheels 54 proximate the center line of the coupled bogies 50a and 50b, and the opposite end loop of the cable 156 may encompass the respective central frames 56 of the two bogies or reside on one side thereof. Each of the pulleys 158 and 160 is rigidly mounted on an abbreviated shaft 162 that is journalled in a bracket 164, brackets 164 being welded, bolted or otherwise suitably affixed to the respective central frames 56. Rotary motion is transmitted from the double pulleys 158 and 160 to the associated upper guide wheel shaft by other components of the cable-and-pulley unit 138. Specifically, an endless cable 166 is threaded over the lower sheave portion of each double pulley and over a pair of drive pulleys 168 fastened, respectively, to the rear upper guide wheel shaft of bogie 50a and the forward upper guide wheel shaft of bogie 50b. Idler rollers 170 mounted on the frames 56 direct the cable 166 in a path around the other components of the bogie assembly.

While the fail-safe guidance mechanism will be described more fully hereinafter with respect to FlGS.

3-8, 13-15, and 23-25, it will be valuable at this juncture to delineate the construction of that portion of the fail-safe guidance mechanism which is directly operated by the cable-and-pulley unit 138. Continuing therefore with reference to FIG. 11, a lower guide roller assembly 172 is fastened to each shaft 162 to rotate generally with the corresponding double pulley. Each of the assemblies 172 includes a T-shaped frame 174 comprising a lower guide wheel arm 176 and a yoke 178. The arm 176 is non-rotatably attached to the shaft 162 and carries a rotatable lower guide roller 180 in upright position, yoke 178 being rotatably affixed to the shaft 162. A pair of outboard cam rollers 182 are rotatably mounted on the yoke 178 in upright position.

lt is contemplated that a system of mechanical linkages could be substituted for the cable-and-pulley unit 138.

Turning now to FIG. 18 for a description of the construction of the pneumatic actuating cylinder or jack 136, that unit comprises, in addition to the extensible and retractable piston rod 142, a cylindrical housing or shell 184, a piston 186 secured to the rod 142, and a pair of end plate members 188 and 190. The piston 186 is longitudinally slidably disposed within the housing 184 and an O-ring 192 is situated in an annular, radially outwardly opening groove 194 to provide a seal between the piston and the housing. The piston 186 is secured to the rod 142 by a pair of longitudinally spaced retainer rings 196, the rod 142 being fashioned with grooves 198 for reception of these rings. A small O-ring 200 is situated in a groove 202 located centrally of the piston 186 to form a seal between the piston and the rod 142.

The end plate member 188 is similarly provided with inner and outer seals, specifically a radially outwardly disposed O-ring 204 which seals against the inner wall of housing 184 and a radially inwardly disposed O-ring 206 which effectuates a seal against the rod 142. The end plate member 188 is securely fastened in permanent position by means of a pair of spaced retainer rings 208 which are fitted into appropriate grooves fashioned in the inner side wall of the housing 184.

The end plate member 190 is likewise secured and sealed in the housing. In particular, an outer O-ring 210 is situated in a groove 212 formed in the end plate member to confront the inner wall of housing 184 and provide a seal thereagainst; and an O-ring 214 is located in a groove 216 to confront the piston rod 142 and provide a seal against that element. A pair of longitudinally spaced retainer rings 218 are received in grooves formed in the inner side wall of housing 184 to hold the member 190 in place.

As will be appreciated, the piston 186 divides the space between the end plate members 188 and 190 into a pair of variable volume chambers 220 and 222; and a combination inlet-outlet line 224 which is fastened to the side wall of housing 184 by a mounting block 226 and communicates with the chamber 220 through a lateral aperture 228 fashioned in the side wall of housing 184. The mounting block 226 also receives threadedly a set screw 230 which normally closes a vent port 232 and which is secured in place by a locknut 234. The chamber 222 likewise communicates with an inlet and outlet line 236 through a port 238 fashioned in the sidewall of housing 184, the end of line 236 being fastened to the housing 184 by a mounting block 240. A vent port 242 is normally closed by a set screw 244 that is secured by a locknut 246.

In compliance with the features of the present invention, the pneumatic jack 136 is arranged to take a locked position when the bogies and guideway are in the normal running mode and to be unlocked in the event of a leak or failure of the pneumatic system or in the event of a failure in the electrical control circuitry. For this purpose, the end plate member is provided with a tubular extension portion 248 which passes slidably through a piston 250. A suitable number of ball bearings 252 are located in a semitoroidal groove 254 formed in the periphery of piston rod 142 to establish a lock in the manner to be described shortly, and the extension portion 248 is apertured to pass the ball bearing 252 radially into an unlocked position. An O-ring 256 establishes a seal between the piston 250 and the housing 184, and an O-ring 258 provides a seal between the piston 250 and the extension portion 248. In order to provide a stop for the piston 250, the extension portion 248 is fashioned with an annular shoulder 260 confronting the piston 250. In addition, the extension portion 248 is provided with a relieved section 262 between the shoulder 260 and the adjacent retainer ring 218. An annular chamber 264 is thus defined between the portion 262, the adjacent regions of the extension portion 248 and the piston 250. An inlet-outlet conduit 266 communicates with this annular chamber through a mounting block 268 and a lateral aperture 270 provided in the sidewall of housing 184, aperture 270 being aligned with the space between shoulder 260 and the adjacent retainer ring 218 in order that abutment of the piston 250 with the shoulder 260 will not close off communication with the conduit 266.

The piston 250 is biased toward the shoulder 260 by a compression spring 272 which is confined between a shoulder 274 generated on the piston and a nut 276 which is turned onto the threaded end section 278 of extension portion 248. The piston 250 is provided with a counterbored cavity 280 for purposes which will appear immediately hereinafter.

At the opposite end of the pneumatic cylinder 136, an eyebolt 282 threadedly engages the exposed end portion of piston rod 142 to be secured in position by means of a locknut 284. The eyebolt 282 provides a convenient means for connecting the piston rod to the cable-and-pulley unit 138.

As will be appreciated, the piston rod 142 is locked against movement relative to the cylinder housing 184 when the piston 250 is disposed in the position illustrated in FIG. 18. Specifically, pneumatic pressure in the chamber 264 situates the piston 250 in the illustrated location, compressing the spring 272 and retaining the ball bearings 252 in the groove 254 and between the end section 278 and the remainder of extension portion 248. Thus, the ball bearings 252 lock the piston rod 142 to the stationary extension portion 248. When it is desired to actuate the cable-and-pulley unit 138, the pneumatic pressure in chamber 264 is exhausted through conduit 266, allowing the piston 250 to move against the shoulder 260 in response to the force stored in spring 272. As the piston 250 moves toward the shoulder 260, the cavity 280 is moved into radial alignment with the ball bearings 252 to allow these ball bearings to escape into the cavity and out of the groove 254 thereby releasing the piston rod 142 to the action of piston 186. The piston rod 142 may be returned to its locked position by again pressurizing the chamber 164, the ball bearings 252 being directed into the groove 254 by a conical guide surface 286 disposed at the inner end of cavity 280.

Referring now to FIGS. 3-8, for a description of the stationary switching arrangements associated with the monorail guideway, the box girder unit 58, at a normal running region, has the upper track plates 80 and 84 spaced above the lower track plates 82 and 86 by a distance A, as shown in FIG. 4. This spacing accommodates the neutral position of the upper guide wheels 60 shown in FIG. 2 wherein all of the guide wheels reside in contact with the corresponding upper track plates. In addition, the lower track plates 82 and 86 are provided with inner edges 288 and 290 respectively which are elevated slightly above the corresponding outer edges at the flanges 130. This cambering of the lower track plates promotes even tracking of the main drive wheels during transit of the bogies through the guideway.

The guideway section illustrated in FIGS. 3-8 is that section of the switching station in which the bogies are readied to negotiate a divergence or convergence of the vehicle routes; and the first guideway transforma tion in the guideway configuration comprises a gradual increase of the spacing between the upper and lower track plates to the dimension B shown in FIG. 5. This increase in the spacing between the upper and lower track plates allows rotation of the upper guide wheel shaft 62 so as to lower either the port or starboard upper guide wheels while raising the opposite upper guide wheels in the manner illustrated generally in FIG. 9. It is also advantageous to reduce gradually the camber of the lower track plates 82 and 86 as the spacing between the lower and upper track plates is gradually increased.

The next transformation of the guideway includes the initiation of a pair of pendent inboard flanges or guide wall members 292 and 294 from the ceiling of the guideway as is shown in FIG. 6. These flanges cooperate with corresponding outboard flanges or guide wall members 296 and 298 and with the upper track plates 80 and 84 to define a pair of downwardly opening slots or channels 300 and 302 respectively. These slots or channels capture and retain the elevated set of upper guide wheels as is shown in FIG. 9. With the appearance of the flanges 292 and 294, the camber of lower track plates 82 and 86 continues to recede, and these occurrences are accompanied by the initiation of the first pendent cam blade 304 which is secured to the lower track plate 86 as is shown in FIGS. 3 and 6. With reference to FIG. 3, the cam blade 304 curves from a generally outboard position 306 to a more inboard position 308. Furthermore, the cam blade 304 cooperates with a second cam blade 310 in defining the stationary members of the fail-safe guidance arrangement. Like the cam blade 304, the cam blade 310 curves from a generally outboard position 312 to a more generally inboard position 314. The cam blades 304 and 310 are advantageously arranged as constant acceleration cams. The cam blades 304 and 310 coact with the roller assemblies 172 in a manner to be described more fully hereinafter with reference to FIGS. 13-15, 20 and 23-25.

The arrangement shown in FIG. 7 illustrates the final transition before the guideway 32 develops a switching gap or enlargement of the space between the lower track plates 82 and 86. At this juncture, a port side lower steering blade 316 has appeared, and the camber of the lower track plates 82 and 86 has been completely eliminated. A short distance downstream from this point, a starboard lower steering blade 318 appears, steering blades 316 and 318 being secured respectively to the inner edges of lower track plates 86 and 82 and having respective laterally outwardly facing steering surfaces. As will be seen in FIG. 13, the steering blades 316 and 318 continue through the switching section until such point as the switching maneuver has been accomplished.

In accordance with the present invention, means are provided for insuring a continuous supply of electric power to the bogie assemblies during transit through a switching section. Specifically and with reference to FIGS. 16 and 17, electricity is normally supplied to the bogie assemblies from the overhead electric power bus arrangement 64 which is mounted in the ceiling of the guideway 32 at ordinary running sections of the guideway. A power pickup 320 is mounted on the main frame 56 of fore bogie 50a by means of a mounting plate 322 and a suitable number of coil springs 324, springs 324 urging a collector carriage 326 upwardly toward the power bus arrangement 64. The bus arrangement 64 includes three power conductors 328 which terminate in pendent, conductive channels 330. Cooperatively, the collector carriage 326 includes three upstanding collector bars 332 which ride in the channels 330 in sliding contact with the walls of the channels in order to lead power through a cable 334 to the motor and other electrically operated components of the bogie. The conductors 328 are housed in an insulating block 336 and receive power from respective lines 338. In addition, the collector carriage 326 includcs insulative side guides 340 and inboard insulative bars 342.

In order to avoid unduly complicated electrical arrangements at the cross-over region of a switching station and in order to insure continuity of electrical supply, the guideway 32 is provided with oppositely disposed, electrically insulative sidewall panels 344 at the switching section; and a laterally disposed power bus arrangement 346 is mounted to each of the panels 344 to supply power to the bogie during transit through the cross-over region. Each power bus arrangement 346 includes three vertically spaced, horizontally disposed rectangular conductors 348, and each conductor 348 is supplied with current through a cable 350. A pair of power collectors 352 are laterally swingably mounted to an extension portion 354 of the main frame 56 for taking power off of a lateral bus arrangement 346, and it will be appreciated that two such collectors are provided in order that suitable electric circuits may be completed regardless of whether the bogie is in the lefl-hand turn or right-hand turn condition. Each of the collectors 352 comprises an insulative panel 356 to which there are affixed three pairs of conductive brushes 358. Each brush 358 makes sliding electrical contact with the conductors 348, and suitable electrical connections are accomplished by means of cables 360.

It has proved advantageous to mount the collectors 352 so that they may be moved laterally to the proper position during transit through a switching section. It has also proved desirable to provide for positioning of the collectors 352 in coordinated fashion with the upper guide wheels 60 and the lower guide wheels 180. With reference now to FIGS. 21 and 22 and with particular reference first to FIG. 21, each of the insulative panels 356 is mounted to a triangular cage 362 which is itself swingably mounted to the extension 354 by two horizontal links 364 and a pair of pivot pins 366 and 368, pivot pin 368 being a common connection for the links 364 at the frame extension 354. The cages 362 are biased in the generally forward direction by means of tension springs 370 which are connected between the cages and respective flanges 372 extending laterally from the main frame 56. Powered control of the motion of the cages 362 and therefore the brushes 358 is accomplished by means of horizontally reciprocal links 374 which are swingably mounted to the cages by pins 376 and which are joined to generally vertically disposed links, indicated in FIG. 22 by the reference numeral 378, by means of ball-and-socket units 380.

Continuing with reference to FIG. 22, the links 378 are both journalled on a horizontal shaft 382 and carry cam rollers 384 at their upper ends. The shaft 382 is supported between a pair of upwardly inclined arms 386 which are afiixed to the main frame 56, and a tension spring 388 biases each cam roller 384 into engagement with a corresponding cam 390, the cams 390 being rigidly secured to the upper guide wheel shaft 62 for actuation by means of the cylinder 136 and the cable-and-pulley unit 138.

It is contemplated that the overhead power bus arrangement may be eliminated entirely and the lateral power bus arrangements be relied on exclusively for power collection. In the latter instance, the described means for repositioning the brush cages 362 ensures a synchronized break-before-make action of power collection from one side of the guideway to the other during negotiation of a switch.

As described hereinabove with reference to FIG. 2, all of the upper guide wheels 60 are pre-loaded against the guideway ceiling when operating in their neutral or normal running conditions. This pre-loading permits the upper guide wheels to provide rotational and pitch restraint for the vehicle; and in addition, the lateral friction between these wheels and the guideway ceiling provides a yaw restraint. As described with reference to FIG. 2, all four of the upper guide wheels 60 are positioned in rollable contact with the guideway ceiling in this normal running condition, pre-loading of these upper guide wheels being accomplished by proper selection of the distance between the lower track plates and the upper track plates, that is, the dimension A illustrated in FIG. 4. The dimension A is selected so that, upon full inflation of the pneumatic tires 132 and despite a loading of the vehicle 38 to its full capacity, the upper guide wheels are situated in forcible contact with the upper track plates 80 and 84. This creates a moderate lateral distension of the tires 132 as is shown in FIG. 12.

Continuing with reference to FIG. 12, the tires 132 are mounted on wheel rims 392 and 394, the rim 394 being provided with a flange which is formed into a driven pulley 396. The rim of pulley 396 is appropriately grooved to receive the drive belts 106.

In order to mount the wheel rims 392 and 394 to the main frame 56, bearing assemblies 398 are rigidly affixed to the main frame; and hub units 400 are secured on the rotatable outer member of the respective bearing assemblies. Each hub unit 400 includes a hemispherical body 402 which abuts the edge of a central aperture 404 in the wheel rim, each hub unit additionally including a radially outwardly extending flange 406 which is drilled to pass mounting bolts 408. Bolts 408 extend slidably through appropriately sized apertures in the wall of the wheel rim to receive mounting nuts 410 on their threaded ends. The bolts 408 and the nuts 410 may also be employed in mounting the safety wheels 134 as is suggested in the left-hand portion of the figure. In addition, the flanges 406 advantageously terminate in collars or drums 412 which cooperate with shoes 414 of conventional automotive type brakes.

In compliance with the features of the present invention, the lower guide roller assemblies 172 are constructed so as to unlock the pneumatic cylinder 136 in an equipment failure situation, this being done so that the cam rollers 182 may cooperate with the fail-safe cam arms 304 and 310 in efi'ectuating proper route selection. More specifically, motion in the connection between the lower guide wheel am 176 and the cam roller yoke 178 is sensed electrically, and the resultant signal is used to trip the lock of cylinder 136.

With reference to FIG. 20, a slip ring switch 416 is configurated to trip on relative motion between the arm 176 and the yoke 178, the yoke 178 being centered on the arm 176 by opposed tension springs 415. Turning for the moment to FIGS. 23 and 24, the switch 416 includes a top switch plate 418 which is fabricated from an electrically conductive material, such as stainless steel, and which is attached to a bracket portion of the lower guide wheel arm 176. An insulator 422 is advantageously disposed between the plate 418 and the bracket portion 420 to prevent electrical contact. In addition, a pair of electrically insulative inserts 424 are situated in spaced recesses formed in the top plate 418 to define a conductive track 426 therebetween as is best seen in FIG. 24. A bracket portion 428 of the yoke 178 secures a switch housing 430 in horizontal alignment with the top plate 418; and a switch pin 432 is slidably mounted in the housing 430 to be urged into mechanical and electrical contact with the conductive edge of top switch plate 418 by a compression spring 434.

Cooperatively disposed with respect to the top switch plate 418 and arranged for movement with the cam roller yoke 178 is a bottom switch plate 436 which is mounted to the yoke 178 by suitable means such as screws, not shown, a bottom switch insulator 438 being disposed between the bottom switch plate 436 and the yoke in order to provide electrical insulation. The bottom switch plate 436 carries a generally boomerangshaped spring 440 which is fabricated from an electrically conductive spring material such as beryllium copper and which carries a contact element 442 in biased engagement with the underside of top switch plate 418. So situated, the contact 442 is able to complete a circuit from the conductive channel 426 to a switch pin 444 contained in a switch housing 446 through a conductive insert 448 and a pair of rivets 450 which mount the boomerang-shaped spring 440 to the bottom switch plate 436. As with the case of switch pin 432, the switch pin 434 is biased toward the corresponding switch plate by means of a compression spring 452. Cables 454 and 456 complete an electrical control circuit which serves to exhaust the chamber 264 of pneumatic jack 136 through a normally closed, solenoid-operated valve upon breaking of the associated circuit through contact 442 being displaced from conductive channel 426 and onto either of the insulative inserts 424.

Having thus described one construction of the invention, it is important now to state how the illustrated embodiment operates in both its normal running mode and the failure situation.

The normal running configuration of the bogies 50 and the guideway 32 is illustrated generally in FIGS. 2 and 4; and these configurations appear at portions of the guideway not actually comprising a switching station, an approach to a switching station, or a departure from a switching station. In this normal running mode, the vehicle 38 is supported from both the port and starboard main drive wheels of each bogie assembly; and the upper guide wheels 60 are urged uniformly into forcible engagement with the upper track plates, the upper guide wheels being carried in the level or neutral condition by the pneumatic cylinder 136 which is locked in this configuration. As described hereinabove, forcing of the upper guide wheels into contact with the upper track plates preloads the pneumatic tires 132 and promotes stability in vehicular transit. The camber of the lower track plates 82 and 86 cooperates in promoting this stability.

In this normal operating mode, the energy for the propulsion motors 100 and 102, as well as that for other electrical components, is collected from the overhead power bus arrangement 64. Furthermore, the lower guide wheels 180 are situated in the neutral condition aligned longitudinally of the coupled bogies 50a and 50b as is shown in FIG. 11. Lateral restraint in this transportation mode is accomplished by the paired lower wheels I24 and the paired upper wheels 118. At the entrance or approach to a switching station, an information signal is received in the control circuitry for the vehicle propulsion arrangement; and this signal is timed to coincide generally with the beginning of the first order alteration of the guideway configuration (illustrated in FIG. 5). This information signal is used to unlock the pneumatic cylinder through control of the pressure in chamber 264 and contains the sense information indicating which of the routes immediately ahead has been selected for travel. The information signal is also used to actuate the pneumatic cylinder 136 for raising the selected upper guide wheels 60 and rotating the lower guide roller assemblies 172 through the cable-and-pulley unit 138. This rotation of the assemblies 172 situates the lower guide rollers 180 so that they will operate outboard of the selected route steering blade 316 or 318 (as is suggested in FIG. 13 in broken outline). Such relative motion between the lower guide roller arm 176 and the cam roller yoke 178 as is experienced during this rotation has no effect on the various guidance activities since the pneumatic cylinder 136 has previously been unlocked by the information signal.

Second and third order alterations of the guideway configuration are shown respectively in FIGS. 6 and 7 where the guide rollers selected for guidance activity will have been captured by one of the pendent plates 292 and 294; and the lower guide wheels will have been situated outboard of the corresponding steering blade 316 or 318. In addition, the camber of the lower track plates 82 and 86 will have disappeared. As will be appreciated, in this normal, switch approach, the cam rollers 182 will have been rotated in powered fashion and will have not engaged either of the fail-safe cam blades 304 and 310.

As the vehicle approaches the switching station and begins the actual negotiation of that region of the switching station where the track plates experience a lateral spacing wider than normal, application of power to the main drive wheels 54 will be continued; but all of the combined vehicle and passenger load will be borne by either the port or starboard wheels in accordance with the selected switching configuration. During this transitional configuration, electrical supply is supplied from one of the laterally disposed power bus arrangements 346. Furthermore, the reaction loads on turning will be taken up by the cooperation of lower guide wheel 180 and the selected lower steering blade and by the corresponding upper guide wheels and the associated pendent blade 292 or 294. This transitional configuration is illustrated generally in FIG. 9.

Upon passing through the switching station, the guidance elements will be returned to the neutral configuration in reverse sequence. The vertical spacing between the upper and lower track plates will decrease; the blades 292, 294, 316 and 318 will disappear; the camber of the lower track plates 82 and 86 will reappear; and the pneumatic cylinder 136 will be actuated to re-situate the upper guide wheels 60 in neutral condition and will itself be locked in its neutral condition.

In the failure mode of operation, a substantially similar approach will be made to the switching section inasmuch as all of the switching gear on the guideway is static and does not change in response to the failure condition. However, the turn signalling circuitry or the pneumatic control system will have experienced a failure, and the lower guide roller assembly 172 and the upper guide wheel 60 will not have been rotated into the selected configuration prior to the fore bogie arriving at the initiation of the first fail-safe cam blade.

It is advantageous to arrange the fail-safe cam blades 304 and 310 to direct the vehicle into the mainline direction upon experiencing a system failure; and this type of predetermined vehicle direction is shown in both the left-tum switching station of FIG. 13 and the merging switching station of FIG. 14.

Continuing with reference to FIG. 13, by way of example, initial engagement of the cam blade 304 by the adjacent cam roller 182 will tend to rotate the yoke 178; and because prior failure of either the electrical system not involving switch 416 or the pneumatic system will have prevented unlocking of the cylinder 136, the lower guide wheel 180 will tend to remain in longitudinal alignment with the corresponding bogie due to friction in the corresponding cable-and-pulley unit 138. A resultant relative motion between the lower guide wheel arm 176 and the yoke 178 occur as is suggested in the left-hand portion of FIG. 25. The switch contact 442 will thus be relocated onto one of the insulative inserts 424 to break the holding circuit to the pneumatic cylinder 136, unlocking the cylinder and permitting further response of the lower guide roller assembly to the cam blades 304 and 310. As will be appreciated, the resultant rotation of the guide roller assembly 172 will relocate the upper and lower guide wheels through the interconnection established by the cable-and-pulley unit 138. This preselected rotation of the lower guide roller assembly 172 is shown in FIG. 14 as well as in FIG. 13.

From the foregoing, it will be apparent that a preferred embodiment of the invention has been described with specificity. Equivalents, variations, and modifications of the principles of the invention will be apparent from the specific disclosures herein; and it is intended that the true spirit and scope of the invention be limited only as defined in the appended claims.

The invention is claimed as follows:

1. A vehicle switching arrangement comprising: overhead monorail guideway means including a first mainline upper track plate, a first lower track plate aligned beneath said upper track plate, a second upper track plate spaced laterally from said first upper track plate and having a first section paralleling said first mainline upper track plate and a second section diver gent from said mainline section and cooperating to define a switch, and a second lower track plate aligned beneath said second upper track plate; and bogie means arranged for rollable transport along said guideway means, including port and starboard main wheel means rollably engaging said lower track plates, port and starboard upper guide wheel means carried by said bogie and rollably engageable with said upper track plates, and power-actuated means for forcing a selected one of said port and starboard upper guide wheel means into engagement with one of said first and second upper track plates whereby substantially the entire vehicle load is carried by the selected main wheel means during transit through said switch for establishin g vehicle heading.

2. A vehicle switching arrangement according to claim 1 wherein said bogie means includes fore and aft port main wheel means, fore and aft starboard main wheel means, fore and aft port upper guide wheel means, and fore and afi starboard upper guide wheel means and wherein said power-actuated means includes cable-and-pulley means interconnecting said upper guide wheel means and an actuator coupled to said cable-and-pulley means for directing coordinated movement of said upper guide wheel means.

3. A vehicle switching arrangement according to claim 2 wherein said guideway means further includes substantially vertically disposed steering blade means having laterally outwardly facing steering surfaces and wherein said bogie means further includes lower guide wheel means swingably situatable into guiding engagement with a said steering surface to cooperate in directing transit of said bogie means through said switch, said cable-and-pulley means being connected to said lower guide wheel means for actuation thereof by said actuator.

4. A vehicle switching arrangement according to claim 3 wherein said guideway means further includes substantially vertically disposed cam blade means located upstream from said switch and wherein said lower guide wheel means includes a lower guide wheel for coaction with said steering blade means and a pair of cam followers mounted respectively outboard of said lower guide wheel for engagement with said cam blade means for directing safe transit of said bogie means through said switch in the event said actuator fails to operate properly.

5. A vehicle switching arrangement according to claim 4 wherein said cam followers are cam rollers.

6. A vehicle switching arrangement according to claim 4 wherein said cam blades are constant acceleration cams.

7. A vehicle switching arrangement according to claim 1 wherein said guideway means further includes substantially vertically disposed steering blade means having laterally outwardly facing steering surfaces and wherein said bogie means further includes lower guide wheel means swingably situatable into guiding engagement with a said steering surface to cooperate in directing transit of said bogie means through said switch.

8. A vehicle switching arrangement according to claim 1 wherein said bogie means further includes coupling means interconnecting said upper guide wheel means for coordinated operation, said upper guide wheel means having a neutral position in which said upper guide wheel means reside in a common overhead planar position, said upper and lower track plates being disposed a first distance apart in normal running sections thereof and in a second, greater distance in the switch section thereof whereby to permit situation of the selected one of said port and starboard guide wheel means in engagement with a selected upper track plate and the other of said port and starboard guide wheel means away from the other of said upper track plates.

9. A vehicle switching arrangement according to claim 8 wherein said bogie means further includes guide wall means pendent from each of said upper track plates in said switch section for restraining said selected one of said guide wheel means against lateral movement.

10. A vehicle switching arrangement according to claim 1 wherein said bogie means further includes guide wall means pendent from each of said upper track plates in said switch section from restraining said selected one of said guide wheel means against lateral movement.

11. A vehicle switching arrangement according to claim 1 wherein said bogie means further includes upper and lower lateral restraint means.

12. A vehicle switching arrangement according to claim 11 wherein said guideway means further includes sidewall means and wherein said lateral restraint means comprise wheels rollably engageable with said sidewall means.

13. A vehicle switching arrangement according to claim 1 wherein said bogie means includes electric motor means drivingly connected to said main wheel means; wherein said guideway means includes electrical power bus means mounted interjacent the respective upper and lower track plates; and wherein said bogie means further includes lateral electrical power collector means engaging said power bus means.

14. A vehicle switching arrangement according to claim 13 wherein said bogie means includes poweroperated means connected to said lateral electrical power collector means for moving said lateral electrical power collector means into and out of engagement with said second power bus means.

15. A vehicle switching arrangement according to claim 14 wherein the power-actuated means for said upper guide wheel means includes cable-and-pulley means interconnecting said upper guide wheel means and an actuator coupled to said cable-and-pulley means; and wherein said power-operated means includes link means connected to said lateral electrical power collector means and to said cable-and-pulley means.

16. A vehicle switching arrangement according to claim 1 wherein said bogie means includes electric motor means drivingly connected to said main wheel means; wherein said guideway means includes first electrical power bus means mounted adjacent said upper track plates in said mainline section and second electrical power bus means mounted interjacent the respective upper and lower track plates adjacent said switch; and wherein said bogie means further includes upper electrical power collector means engaging said first power bus means during normal transit and lateral electrical power collector means engaging said second power bus means during transit through said switch.

17. A vehicle switching arrangement according to claim 1 wherein said power-actuated means includes an actuator having a cylindrical housing, piston rod means extensibly and retractably disposed in said housing, abutment means fixed relative to said housing, locking piston means slidably mounted on said piston rod means, locking means acting between said abutment means, said piston rod means and said locking piston means to lock said piston rod means relative to said housing in one position, and means biasing said locking piston means away from said one position whereby to allow unlocking of said piston rod means upon failure of the fluid supply to said actuator.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,702,590 Dated November l4 1972 lnventol-(s) Robert W. Corey It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 63 and Column 2, line 13, change "and elevational View" to --end elevational view--;

Column 2, line 47, change "section" to --sectional-.

Signed and sealed this 22nd day of May 1973.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents FORM POJOSO (O-69) USCOMMQDC 0375 35 #1 us. GOVERNMENT PRINTING OFFICE 1969 0-366-334 

1. A vehicle switching arrangement comprising: overhead monorail guideway means including a first mainline upper track plate, a first lower track plate aligned beneath said upper track plate, a second upper track plate spaced laterally from said first upper track plate and having a first section paralleling said first mainline upper track plate and a second section divergent from said mainline section and cooperating to define a switch, and a second lower track plate aligned beneath said second upper track plate; and bogie means arranged for rollable transport along said guideway means, including port and starboard main wheel means rollably engaging said lower track plates, port and starboard upper guide wheel means carried by said bogie and rollably engageable with said upper track plates, and power-actuated means for forcing a selected one of said port and starboard upper guide wheel means into engagement with one of said first and second upper track plates whereby substantially the entire vehicle load is carried by the selected main wheel means during transit through said switch for establishing vehicle heading.
 2. A vehicle switching arrangement according to claim 1 wherein said bogie means includes fore and aft port main wheel means, fore and aft starboard main wheel means, fore and aft port upper guide wheel means, and fore and aft starboard upper guide wheel means and wherein said power-actuated means includes cable-and-pulley means interconnecting said upper guide wheel means and an actuator coupled to said cable-and-pulley means for directing coordinated movement of said upper guide wheel means.
 3. A vehicle switching arrangement according to claim 2 wherein said guideway means further includes substantially vertically disposed steering blade means having laterally outwardly facing steering surfaces and wherein said bogie means further includes lower guide wheel means swingably situatable into guiding engagement with a said steering surface to cooperate in directing transit of said bogie means through said switch, said cable-and-pulley means being connected to said lower guide wheel means for actuation thereof by said actuator.
 4. A vehicle switching arrangement according to claim 3 wherein said guideway means further includes substantially vertically disposed cam blade means located upstream from said switch and wherein said lower guide wheel means includes a lower guide wheel for coaction with said steering blade means and a pair of cam followers mounted respectively outboard of said lower guide wheel for engagement with said cam blade means for directing safe transit of said bOgie means through said switch in the event said actuator fails to operate properly.
 5. A vehicle switching arrangement according to claim 4 wherein said cam followers are cam rollers.
 6. A vehicle switching arrangement according to claim 4 wherein said cam blades are constant acceleration cams.
 7. A vehicle switching arrangement according to claim 1 wherein said guideway means further includes substantially vertically disposed steering blade means having laterally outwardly facing steering surfaces and wherein said bogie means further includes lower guide wheel means swingably situatable into guiding engagement with a said steering surface to cooperate in directing transit of said bogie means through said switch.
 8. A vehicle switching arrangement according to claim 1 wherein said bogie means further includes coupling means interconnecting said upper guide wheel means for coordinated operation, said upper guide wheel means having a neutral position in which said upper guide wheel means reside in a common overhead planar position, said upper and lower track plates being disposed a first distance apart in normal running sections thereof and in a second, greater distance in the switch section thereof whereby to permit situation of the selected one of said port and starboard guide wheel means in engagement with a selected upper track plate and the other of said port and starboard guide wheel means away from the other of said upper track plates.
 9. A vehicle switching arrangement according to claim 8 wherein said bogie means further includes guide wall means pendent from each of said upper track plates in said switch section for restraining said selected one of said guide wheel means against lateral movement.
 10. A vehicle switching arrangement according to claim 1 wherein said bogie means further includes guide wall means pendent from each of said upper track plates in said switch section from restraining said selected one of said guide wheel means against lateral movement.
 11. A vehicle switching arrangement according to claim 1 wherein said bogie means further includes upper and lower lateral restraint means.
 12. A vehicle switching arrangement according to claim 11 wherein said guideway means further includes sidewall means and wherein said lateral restraint means comprise wheels rollably engageable with said sidewall means.
 13. A vehicle switching arrangement according to claim 1 wherein said bogie means includes electric motor means drivingly connected to said main wheel means; wherein said guideway means includes electrical power bus means mounted interjacent the respective upper and lower track plates; and wherein said bogie means further includes lateral electrical power collector means engaging said power bus means.
 14. A vehicle switching arrangement according to claim 13 wherein said bogie means includes power-operated means connected to said lateral electrical power collector means for moving said lateral electrical power collector means into and out of engagement with said second power bus means.
 15. A vehicle switching arrangement according to claim 14 wherein the power-actuated means for said upper guide wheel means includes cable-and-pulley means interconnecting said upper guide wheel means and an actuator coupled to said cable-and-pulley means; and wherein said power-operated means includes link means connected to said lateral electrical power collector means and to said cable-and-pulley means.
 16. A vehicle switching arrangement according to claim 1 wherein said bogie means includes electric motor means drivingly connected to said main wheel means; wherein said guideway means includes first electrical power bus means mounted adjacent said upper track plates in said mainline section and second electrical power bus means mounted interjacent the respective upper and lower track plates adjacent said switch; and wherein said bogie means further includes upper electrical power collector means engaging said first power bus mEans during normal transit and lateral electrical power collector means engaging said second power bus means during transit through said switch.
 17. A vehicle switching arrangement according to claim 1 wherein said power-actuated means includes an actuator having a cylindrical housing, piston rod means extensibly and retractably disposed in said housing, abutment means fixed relative to said housing, locking piston means slidably mounted on said piston rod means, locking means acting between said abutment means, said piston rod means and said locking piston means to lock said piston rod means relative to said housing in one position, and means biasing said locking piston means away from said one position whereby to allow unlocking of said piston rod means upon failure of the fluid supply to said actuator. 